The study looked at the water and sediment quality in the upper part of the Sampadi River, focusing on areas near oil palm plantations, residential areas, and a coal refinery. They found that during low tide, there were high levels of total suspended solids and nitrate/nitrite nitrogen, while during high tide, there were higher levels of BOD5, TKN, and ammonia nitrogen. Most water quality parameters met Malaysia's standards, except for oil and grease, nitrate nitrogen, nitrite nitrogen, and phosphorus. Sediment quality was influenced by particle size, with finer particles showing higher levels of organic carbon, heavy metals, and nutrients. Sand content had negative correlations with TOC, TKN, and total phosphorus.